I can use it from python flawlessly, but the widget would be SO useful.

I use the latest dev version from the repo ( hg pull; hg update; python setup.py build ) (2.6a2.dev-a66a74b)

Am I doing something wrong. Also, I noticed that during the build (I used some older version, do not know precisely which) the network analysis stuff (Network File, Network From Distances, Net Explorer) disappeared. This is not a problem, I did not use it, I just thought it might be relevant. The PCA widget was never there...

Depending on which distribution you are using, the PyQt4 sip class definitions might be missing (check '/usr/share/sip/PyQt4' directory). They are probably contained in a separate package ('python-qt4-dev' or something similar).